Portable commutator dressing apparatus



April 14, 1964 E. HAUGLAND PORTABLE coMMuTAToR DRESSING APPARATUS Filed Feb. '7, 1962 vw a m. MA .mv N A m HHM om 4 M W. WW .W m fl. M mwl uw Nw .W 0 mv WH Ww MW MW P A A HIIIIIIIM 8 N: A fr Nw R ww hmbw f mmok. QAM RN k www. A A H A A .S M J )Ov J .w I i M /M Nm. QM NV\ w WM Q`QN Nm m; QN QM. 1 \N S \h.v h\ M\ m n vl no W\ WN Wm. Nm. wm. wV/l m\ E SN u m mv YP o@ rU. a. -A A w MN m. ,a l\ f .N @NIM vw.

Vcured by bolts 21a or other similar means.

United States Patent Oiice 3,128,533 Patented Apr. 14, 1964 3,128,533 PORTABLE COMMUTATR DRESSING APPARATUS Earl Haugland, Hampden, N. Dak. Filed Feb. 7, 1962, Ser. No. 171,749 6 Claims. (Cl. 29-27) This invention relates to commutator dressing apparatus and more particularly to a portable motor driven device for turning down and undercutting the commutators of motors and generators having shafts of different lengths and diameters.

Because of the pitting and grooving of commutators caused by sparking and brush Wear, it is necessary to smooth out the commutator by cutting away a slight amount of the surface which is usually referred to as the turning down process. After the commutator has been turned down, a final dressing step consists in undercutting or removing a portion of the insulation between adjacent commutator bars.

The present dressing apparatus is primarily of a small, portable and motor driven type wherein the armature is rotated and the turning tool is held stationary except for its longitudinal movement over the length of the commutator during the turning down procedure.

One object of the invention is to provide a portable apparatus for dressing armature commutators which will be quickly adjustable whereby to accommodate various length and diameter armature shafts.

Another object is to provide an apparatus as set forth over which utilizes a mounting means for the armature ends which will allow high speed rotation of the armature by means such as a belt drive from an electrically driven source.

A still further object is to provide turning and undercutting apparatus which Will dress a commutator in a minimum of time.

Another object is to provide apparatus as set forth above which is simple in design and operation and thus economical to manufacture.

These and other objects and advantages of this invention will more fully appear from the following description, made in connection with the accompanying drawing, wherein like reference characters refer to the same or similar parts throughout the several views and in which:

FIGURE 1 is a perspective view of the turning and undercutting apparatus;

FIGURE 2 is an enlarged partial cross-sectional top view of FIGURE l showing the relatively adjustable bearing plates together with an armature and the turning and undercutting mechanism, and

FIGURE 3 is an end view of FIGURE 2 taken on line 3 3.

Referring more particularly to FIGURE l, a turning and undercutting apparatus referred to generally as is comprised principally of a pair of spaced bearing plates 11 and 12 which are mounted on a pair of guide rods or tracks 13 and 14. The xed bearing plate 11 is secured to the guide rods by some means, such as welding, while the adjustable bearing plate 12 is provided with a pair of collars 15 and 16 for sliding upon the guide rods whereby the distance between bearing plates may be varied to accommodate various length armatures. As seen in FIGURE 1, each of the collars is provided with a set screw 17 for temporarily xing the position of the adjustable bearing plate 12 once the armature is properly positioned as shown.

Secured to the ends 18 and 19 of the guide rods 13 and 14 are brackets 20 and 21 which stabilize the apparatus 10 during operation. These brackets may be se- With the brackets of sufficient length the apparatus need not be fixedly mounted to, for example, a bench and thus the apparatus is made portable.

Also forming a principal part of the structure are a pair of mounting brackets 22 and 23 which are secured to the end 19 of guide rail 14. Mounted upon the mounting brackets is an electric drive means such as motor 24 which, via belt 25, causes an armature 26 to rotate. The motor is mounted to the brackets 22 and 23y with temporary means such as bolts 27 which are quickly and easily loosened to allow movement of the motor toward or away from the armature 26. This movement will vallow adaptability of the motor to power the rotation of armatures having smaller or larger rotors 28.

The rotor, as seen in FIGURES l and 2, consists principally of the armature poles 29 which are iixedly secured to an armature shaft 30. Positioned upon the armature shaft 30 and between its unthreaded end 31a and the rotor`28 is an armature commutator 32 which, as mentioned above, is the armature element which is subject to pitting and wearing from contact with the spring loaded brushes during use.

Referring now to FIGURE 2, the means for rotatably mounting the armature 26 to the bearing plates will be set forth. Each of the bearing plates 11 and 12 has a bearing bore 33 kand 34 respectively which are axially aligned. Seated within each of these bores 33 and 34, by friction lit, is a tapered bearing 35 and 36 respectively. Thus, a cylindrical surface 37 of bearing 35 is press fitted into mating contact with the bore 33 and the cylindrical service 38 of the bearing 36 is press fitted into mating contact with bore 34. The friction fits are provided such that no other fastening devices will be required and so that the tapered bearing itself will not turn at the armature shaft 30 turns.

As noted from FIGURE 2, each tapered bearing 35, 36 has an internal frusto conically tapered recess 39 and 40 which increases in diameter toward the anges 41 and 42. Since most armatures have at least one shaft end such as 31 which is threaded, a threaded cap or cone 43 is utilized to protect the shaft threads during the actual dressing operation. As seen in FIGURE 2, the cone 43 is provided with an outer frusto conically shaped surface 43a which mates With the surface 40. When the cone is sui'liciently tightened upon the threads, rotational forces imparted to the armature 26 from motor 24 will be fully imparted to the cone 43. With a slight amount of lubrication, the surfaces 40 and 43a will have relative rotational movement with little frictional drag.k

Referring to FIGURE 2, the unthreaded armature shaft end 31a is shown positioned within an unthreaded cone adapter 44. The shaft end 31a, depending upon Aits size, is allowed to seek its own diameter with recess 44a. The adjustable bearing plate 12 is of course moved to a position where it will `maintain the armature shaft ends 31 and 31a in positions as shown in FIGURE 2 such that longitudinal movement thereof will be avoided, but not, however, to a tight enough position to cause the parts to bind within the tapered bearings and eventually cause excessive friction. It may, in some instances, be preferable to provide la cone 44 for the unthreaded end having a cylindrical recess for the unthreaded end to seat in rather than a frusto conical recess as shown.

The cleaning and undercutting apparatus will now be set forth. Basically this apparatus consists of a tool assembly 45 which is manually moved in a longitudinal direction, parallel with the armature shaft, by a handle means referred to generally as 46 (see FIGURE 1).

More specifically, a collar or sleeve 47 is inserted through the iXed bearing plate 11 and then secured thereto by means such as a welding at 48. As seen in FIG- URES 2 and 3, a short tubular piece 49 is slidably journaled through the collar 47 and is held in constant angular orientation by means of a key 50 on the tubular piece 49 and a matching keywaySl in the collar. Thus rotational torque exerted by the tool assembly 45 during a cutting operationwill be resisted and the tool assembly maintained in proper orientation with respect to the commutator.

The handle means 46 comprises a handle shaft 52 (see FIGURE 1) which is pivotally secured intermediate its ends to the end of tubular piece 49. Shaft 52 in turn terminates upwardly in a handle 53 suitable for being grasped by an individual, and terminates downwardly in a pivotal connection to a pair of link members 54. The other ends of the link members 54 are pivotally cont nec-ted to the end 19 of guide rod 13. The purpose of the j doubly connected link member is to allow a slight axial movement of the handle shaft 52 as it is arcuately swung K during the tool feed operation,

The tool assembly, as noted from FIGURE 2, consists of a threaded feed screw 55, a tool block 56, and a resurfacing and undercutting tool bit 57. In addition, a pair of set screws 58 and 59 are provided for maintaining the lateral position of the tool bit with respect to the commutator 32.

A projecting portion 60 on the tubular piece 49 is provided with a feed screw bore 61 through which the threaded feed screw S is inserted and then held by a crown 62 and a snap ring 63. The feed screw 55, as shown, has a handle 64 which may be easily grasped by an individual whereby to rotate the screw. Threaded v upon the screw 55' is one end 65 of the tool block 56.

Because the threads 66 extend for an appreciable length between the handle 64 and snap ring 63, it is clear that a sufficient range of adjustments may be made of the tool block 56 upon the threaded feed screw. Positioned through the other end 67 of tool block 56 is an opening 68 adapted to receive therethrough the shank 69 of the tool bit 57.

Also positioned through the tubular piece 49 is a pair of aligned openings '70 and 71 on opposite sides thereof. These openings also are adapted to receive the shank 69 of the cutter bit 57. As mentioned previously, set screws 58 and 59 are provided for maintaining the lateral position of the cutter bit 57.

In actual use of the tool assembly, the cutter bit is laterally positioned so that the resurfacing end 72 is positioned closely adjacent the commutator. Then set screw 58 is tightened after which the threaded feed screw is turned until the cutter bit is advanced sufciently so that the resurfacing end is properly positioned for the commutator turning operation. Then set screw 59 is tightened to rigidly hold the shank 69. With the cutter bit in this position and the armature turning under power of motor 24, the handle 53 is arcuately swung whereby to cause a cutting end 72. to slowly traverse the length of the commutator and cause cutting thereof.

When the commutator has been turned down sufficiently, the motor is shut off and the tool bit is turned end for end whereby an undercutting tip 73 is then positioned adjacent an insulator strip 74 located between commutator bars. After manually rotating the armature to the proper angular position, the undercutting tool is forced along the commutator length by swinging the handle 53 thereby undercutting the insulation from between the commutator bars. After the tool is retracted from the now formed groove, the armature may again be turned until the next insulation strip is aligned with the undercutting tool. When all insulation strips have thus been undercut, there will be no tendency for the insulation to raise and wear against the brushes during the actual motor or generator operation.

FIGURE 2 has disclosed a cone 44 which is positioned within the tapered recess 39. If an armature shaft 30 is encountered wherein the unthreaded end 31a is too large for the recess 44a, then cone 44 may be removed and the i end 31a of the shaft allowed to rotate within recess 39 of the tapered bearing 3S.

Since different armatures will have the differently sized shafts, additional cones 43 may be provided to accommodate the variously sized threads of shaft end 31,

It is also pointed out that an electric hand drill may just as well be utilized in place of motor 24 as the electric drive means. This idea is very common in present day practice and will be recognized as a very convenient mode of electric power.

it will, of course, be understood that various other changes may be made in the form, details, arrangements and proportions of the parts without departing from the scope of this invention as set forth in the appended claims. Y

What is claimed:

l. A portable dressing apparatus for turning down motor and `generator armature commutators and the like, said armatures having a shaft at least one end of which is threaded, said apparatus comprising, a pair of spaced and parallel bearing plates the distance therebetween being variable, a tapered bearing secured to each bearing plate and in axial alignment, each said tapered bearing having an internal `frusto conically shaped recess opening inwardly toward the other tapered bearing, means adapted for being secured to the threaded end of said armature and cooperatively interfitting with one of said tapered bearings whereby the armature may be rotatably bridged between said tapered bearings, means for rotating said armature, and a tool means ifor turning do-wn said armature commutator.

2. A portab-le dressing apparatus for turning down motor and `generator armature corn-mutators and the like, said armature having a shaft, one end of which is threaded and the other of which is Unthreaded, said apparatus comprising, a pair of spaced and parallel bearing plates the distance therebetween being variable, a tapered bearing secured to each bearing plate and in axial alignment, each said tapered bearing having an internal frusto conically shaped recess opening inwardly toward the other tapered bearing, a frusto conically shaped cap having an axial threaded opening adapted to be secured to the threaded end of said armature and cooperatively interiitted with one of said tapered bearings, a frusto conically shaped cone adapter having a smooth axial frusto conical opening adapted to intertit between the other of said tapered bearings and the Unthreaded end of said shaft whereby the armature may be rotatably bridged between said tapered bearings, electrical drive means for rotating said armature, and a tool means for turning down said armature commutator.

3. A portable dressing apparatus for turning down motor and generator armature commutators and the like, said armatures having an armature shaft extending axially therethrough and terminating outwardly in a pair of ends, said apparatus comprising, a fixed bear-ing plate, a pair of parallel guide rods extending from one side of said plate, a second bearing plate slidable along said rods into various parallel positions with respect to said first plate, a bearing member carried by each of said plates :in axial alignment with each other, each of said bearing members having an internal frusto conical recess opening inwardly toward the other of said bearings, a pair of cap members for receiving the ends of said armature shaft, each cap member having a frusto conical exterior complementing that of the recesses of said bearings so as to be rotatably supported therein when said second bearing plate is moved into the proper parallel position with respect to said first plate, a tool means adap-ted for turning down said commutator, and means for rotating said armature.

4. A portable dressing apparatus as set forth in claim 3 wherein said plates have apertures for the accommodation of said bearing members and said bearing members are provided with flanges for abutting the inwardly facing sides of said plates.

5. A portable dressing apparatus as set forth in claim 3 including a pair of collars ixedly attached to said second plate and encircling said guide rods, and a set screw threadedly carried by at least 'one collar for retaining said second plate in a selected position with respect to said first plate.

6. A portable dressing appartus as set forth in claim 5 wherein said tool means includes a tool supporting member slidably carried by said rst plate, said tool supporting member being constrained for reciprocable 6 movement in a path parallel to` the axis on which said bearing members are located.

References Cited in the tile of this patent UNITED STATES PATENTS 309,288 Birkmann Dec. 16, 1884 1,184,548 McAleXander May 23, 1916 1,786,442 Miller Dec. 30, 1930 1,823,642 Brown e-t al. Sept. 15, 1931 1,923,416 Blorngren Aug. 22, 1933 2,061,398 Green Nov. 17, 1936 2,145,091 `Mansfield Jan. 24, 1939 

1. A PORTABLE DRESSING APPARATUS FOR TURNING DOWN MOTOR AND GENERATOR ARMATURE COMMUTATORS AND THE LIKE, SAID ARMATURES HAVING A SHAFT AT LEAST ONE END OF WHICH IS THREADED, SAID APPARATUS COMPRISING, A PAIR OF SPACED AND PARALLEL BEARING PLATES THE DISTANCE THEREBETWEEN BEING VARIABLE, A TAPERED BEARING SECURED TO EACH BEARING PLATE AND IN AXIAL ALIGNMENT, EACH SAID TAPERED BEARING HAVING AN INTERNAL FRUSTO CONICALLY SHAPED RECESS OPENING INWARDLY TOWARD THE OTHER TAPERED BEARING, MEANS ADAPTED FOR BEING SECURED TO THE THREADED END OF SAID ARMATURE AND COOPERATIVELY INTERFITTING WITH ONE OF SAID TAPERED BEARINGS WHEREBY THE ARMATURE MAY BE ROTATABLY BRIDGED BETWEEN SAID TAPERED BEARINGS, MEANS FOR ROTATING SAID ARMATURE, AND A TOOL MEANS FOR TURNING DOWN SAID ARMATURE COMMUTATOR. 